Question 1

Which of the following best describes the role of muscle tension during skeletal muscle contraction?

Accepted Answer

Muscle tension is the force produced by the muscle during contraction.

Question 2

A motor unit consists of:

Accepted Answer

A motor neuron and all the muscle fibers it innervates.

Question 3

During a muscle twitch, which phase corresponds to the time when cross bridges are active and the muscle is generating force?

Accepted Answer

Period of contraction

Question 4

If the frequency of stimulation increases and the muscle does not have time to relax between stimuli, what is the result?

Accepted Answer

Fused (complete) tetanus

Question 5

Which equation best represents the relationship between force ($$F$$), cross-sectional area ($$A$$), and stress ($$\sigma) in $$muscle physiology?

Accepted Answer

$$\sigma = \dfrac{F}{A}$$

Question 6

Which of the following mechanisms is NOT a way that ATP is regenerated in skeletal muscle during contraction?

Accepted Answer

Passive diffusion of ATP from the bloodstream

Question 7

A patient is unable to maintain muscle tone in their limbs. Which of the following is most likely impaired?

Accepted Answer

Spinal reflexes and mechanoreceptor activity

Question 8

Which of the following best explains why smooth muscle can maintain contraction for prolonged periods with little energy cost?

Accepted Answer

Smooth muscle contracts and relaxes more slowly, allowing for energy efficiency.

Question 9

The optimal sarcomere operating length for maximal contractile force is:

Accepted Answer

80%–120% of resting length

Question 10

Which of the following is TRUE regarding the recruitment of motor units during increasing strength of stimulation?

Accepted Answer

Smaller motor units are recruited first, followed by larger ones as stimulus intensity increases.

Question 11

Which of the following best describes the difference between smooth and skeletal muscle innervation?

Accepted Answer

Skeletal muscle is innervated by somatic motor neurons, while smooth muscle is innervated by autonomic neurons.

Question 12

A muscle fiber is stimulated at a frequency that allows partial relaxation between contractions. What is this phenomenon called?

Accepted Answer

Unfused (incomplete) tetanus

Question 13

Which of the following is the correct sequence of events in a muscle twitch?

Accepted Answer

Latent period → Period of contraction → Period of relaxation

Question 14

Which of the following is a function of ATP during muscle contraction?

Accepted Answer

Restores resting membrane potential by pumping sodium out and potassium in

Question 15

Which of the following best explains why muscle fibers contract asynchronously during recruitment?

Accepted Answer

To prevent muscle fatigue and allow smooth, sustained contractions.

Question 16

Which of the following is TRUE regarding the length-tension relationship in skeletal muscle?

Accepted Answer

Maximal force is generated when sarcomeres are at 80%–120% of their resting length.

Question 17

Which of the following is a characteristic of smooth muscle contraction compared to skeletal muscle?

Accepted Answer

Smooth muscle maintains contraction for longer periods with less energy.

Question 18

Which of the following best describes the effect of increasing stimulus intensity on muscle contraction?

Accepted Answer

It increases the number of motor units recruited, resulting in greater contractile force.

Question 19

Which of the following is the correct formula for calculating the total force ($$F_{total}) $$produced by multiple motor units, if each unit produces force $$F_i$$?

Accepted Answer

$$F_{total} = \sum_{i=1}^{n} F_i$$

Question 20

Which of the following is a real-world example of muscle tone in action?

Accepted Answer

Maintaining posture while standing upright

Muscles and Muscle Tissue: Skeletal Muscle Contraction and Twitch Responses

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